Studies on delayed cutaneous hypersensitivity reactions in viral hepatitis type B infection are being pursued. Preparation of polypeptides from intact 22-nm hepatitis B surface (HBs) antigen-containing particles which retain immunogenicity but which are free of host cell components is continuing. Recovery of individual polypeptides has been optimized: approximately 60-70% of each protein can be recovered in greater than 95% purity. In view of the interest generated by the observation that HBeAg might be a reliable marker for HB virus infectivity, an effort is being made to purify and characterize HBe antigen so that a more sensitive assay system can be developed. Initial attempts to bind HBeAg to silicic acid, resin-impregnated strips, DEAE-sepharose, or filter paper using glutaraldehyde as a preliminary step in assay development have been unsuccessful.